With fuel economy a global issue for all motor vehicles, any weight reduction for the engine would increase the fuel economy. It is also desirable to reduce wear and tear on the piston, the cylinder and the piston rod with a linear movement of the piston rod. See U.S. Pat. No. 5,158,046 (1992) to Rucker. Rucker's FIG. 5 shows a two piston opposed cylinder engine with linear movement of the two piston rods.
The present invention offers the power of two pistons with each piston by firing a power stroke from both the top and bottom of each piston. The power of an eight cylinder engine can be derived from the cylinder block of a four in line cylinder block. Linear piston rod movement reduces wear and tear.